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authorStefano Stabellini <sstabellini@kernel.org>2017-10-30 15:40:55 -0700
committerBoris Ostrovsky <boris.ostrovsky@oracle.com>2017-10-31 09:05:53 -0400
commitcb1c7d9bbc878a67af270ccd2d23f6d1450579db (patch)
tree6c8da668a5439ca54d5c6dfb72137c665eb680bc /drivers/xen
parent2195046bfd69e487d9a76dc47840f15c8412840c (diff)
xen/pvcalls: implement connect command
Send PVCALLS_CONNECT to the backend. Allocate a new ring and evtchn for the active socket. Introduce fields in struct sock_mapping to keep track of active sockets. Introduce a waitqueue to allow the frontend to wait on data coming from the backend on the active socket (recvmsg command). Two mutexes (one of reads and one for writes) will be used to protect the active socket in and out rings from concurrent accesses. Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: boris.ostrovsky@oracle.com CC: jgross@suse.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Diffstat (limited to 'drivers/xen')
-rw-r--r--drivers/xen/pvcalls-front.c158
-rw-r--r--drivers/xen/pvcalls-front.h2
2 files changed, 160 insertions, 0 deletions
diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index 326395d09e31..8d4a43e6aa46 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -59,6 +59,18 @@ struct sock_mapping {
bool active_socket;
struct list_head list;
struct socket *sock;
+ union {
+ struct {
+ int irq;
+ grant_ref_t ref;
+ struct pvcalls_data_intf *ring;
+ struct pvcalls_data data;
+ struct mutex in_mutex;
+ struct mutex out_mutex;
+
+ wait_queue_head_t inflight_conn_req;
+ } active;
+ };
};
static inline int get_request(struct pvcalls_bedata *bedata, int *req_id)
@@ -121,6 +133,18 @@ static void pvcalls_front_free_map(struct pvcalls_bedata *bedata,
{
}
+static irqreturn_t pvcalls_front_conn_handler(int irq, void *sock_map)
+{
+ struct sock_mapping *map = sock_map;
+
+ if (map == NULL)
+ return IRQ_HANDLED;
+
+ wake_up_interruptible(&map->active.inflight_conn_req);
+
+ return IRQ_HANDLED;
+}
+
int pvcalls_front_socket(struct socket *sock)
{
struct pvcalls_bedata *bedata;
@@ -196,6 +220,132 @@ int pvcalls_front_socket(struct socket *sock)
return ret;
}
+static int create_active(struct sock_mapping *map, int *evtchn)
+{
+ void *bytes;
+ int ret = -ENOMEM, irq = -1, i;
+
+ *evtchn = -1;
+ init_waitqueue_head(&map->active.inflight_conn_req);
+
+ map->active.ring = (struct pvcalls_data_intf *)
+ __get_free_page(GFP_KERNEL | __GFP_ZERO);
+ if (map->active.ring == NULL)
+ goto out_error;
+ map->active.ring->ring_order = PVCALLS_RING_ORDER;
+ bytes = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
+ PVCALLS_RING_ORDER);
+ if (bytes == NULL)
+ goto out_error;
+ for (i = 0; i < (1 << PVCALLS_RING_ORDER); i++)
+ map->active.ring->ref[i] = gnttab_grant_foreign_access(
+ pvcalls_front_dev->otherend_id,
+ pfn_to_gfn(virt_to_pfn(bytes) + i), 0);
+
+ map->active.ref = gnttab_grant_foreign_access(
+ pvcalls_front_dev->otherend_id,
+ pfn_to_gfn(virt_to_pfn((void *)map->active.ring)), 0);
+
+ map->active.data.in = bytes;
+ map->active.data.out = bytes +
+ XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER);
+
+ ret = xenbus_alloc_evtchn(pvcalls_front_dev, evtchn);
+ if (ret)
+ goto out_error;
+ irq = bind_evtchn_to_irqhandler(*evtchn, pvcalls_front_conn_handler,
+ 0, "pvcalls-frontend", map);
+ if (irq < 0) {
+ ret = irq;
+ goto out_error;
+ }
+
+ map->active.irq = irq;
+ map->active_socket = true;
+ mutex_init(&map->active.in_mutex);
+ mutex_init(&map->active.out_mutex);
+
+ return 0;
+
+out_error:
+ if (irq >= 0)
+ unbind_from_irqhandler(irq, map);
+ else if (*evtchn >= 0)
+ xenbus_free_evtchn(pvcalls_front_dev, *evtchn);
+ kfree(map->active.data.in);
+ kfree(map->active.ring);
+ return ret;
+}
+
+int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr,
+ int addr_len, int flags)
+{
+ struct pvcalls_bedata *bedata;
+ struct sock_mapping *map = NULL;
+ struct xen_pvcalls_request *req;
+ int notify, req_id, ret, evtchn;
+
+ if (addr->sa_family != AF_INET || sock->type != SOCK_STREAM)
+ return -EOPNOTSUPP;
+
+ pvcalls_enter();
+ if (!pvcalls_front_dev) {
+ pvcalls_exit();
+ return -ENOTCONN;
+ }
+
+ bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
+
+ map = (struct sock_mapping *)sock->sk->sk_send_head;
+ if (!map) {
+ pvcalls_exit();
+ return -ENOTSOCK;
+ }
+
+ spin_lock(&bedata->socket_lock);
+ ret = get_request(bedata, &req_id);
+ if (ret < 0) {
+ spin_unlock(&bedata->socket_lock);
+ pvcalls_exit();
+ return ret;
+ }
+ ret = create_active(map, &evtchn);
+ if (ret < 0) {
+ spin_unlock(&bedata->socket_lock);
+ pvcalls_exit();
+ return ret;
+ }
+
+ req = RING_GET_REQUEST(&bedata->ring, req_id);
+ req->req_id = req_id;
+ req->cmd = PVCALLS_CONNECT;
+ req->u.connect.id = (uintptr_t)map;
+ req->u.connect.len = addr_len;
+ req->u.connect.flags = flags;
+ req->u.connect.ref = map->active.ref;
+ req->u.connect.evtchn = evtchn;
+ memcpy(req->u.connect.addr, addr, sizeof(*addr));
+
+ map->sock = sock;
+
+ bedata->ring.req_prod_pvt++;
+ RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
+ spin_unlock(&bedata->socket_lock);
+
+ if (notify)
+ notify_remote_via_irq(bedata->irq);
+
+ wait_event(bedata->inflight_req,
+ READ_ONCE(bedata->rsp[req_id].req_id) == req_id);
+
+ /* read req_id, then the content */
+ smp_rmb();
+ ret = bedata->rsp[req_id].ret;
+ bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
+ pvcalls_exit();
+ return ret;
+}
+
static const struct xenbus_device_id pvcalls_front_ids[] = {
{ "pvcalls" },
{ "" }
@@ -212,6 +362,14 @@ static int pvcalls_front_remove(struct xenbus_device *dev)
if (bedata->irq >= 0)
unbind_from_irqhandler(bedata->irq, dev);
+ list_for_each_entry_safe(map, n, &bedata->socket_mappings, list) {
+ map->sock->sk->sk_send_head = NULL;
+ if (map->active_socket) {
+ map->active.ring->in_error = -EBADF;
+ wake_up_interruptible(&map->active.inflight_conn_req);
+ }
+ }
+
smp_mb();
while (atomic_read(&pvcalls_refcount) > 0)
cpu_relax();
diff --git a/drivers/xen/pvcalls-front.h b/drivers/xen/pvcalls-front.h
index b7dabedf5ccb..63b0417c31d3 100644
--- a/drivers/xen/pvcalls-front.h
+++ b/drivers/xen/pvcalls-front.h
@@ -4,5 +4,7 @@
#include <linux/net.h>
int pvcalls_front_socket(struct socket *sock);
+int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr,
+ int addr_len, int flags);
#endif

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